1. Field of the Invention
This invention relates to an apparatus and means for deploying a rocket engine nozzle extension and especially to pneumatic means for deploying a nozzle extension.
2. Description of the Prior Art
Rocket engines for vehicles operating around space stations, orbital transfer vehicles, and engines of high-orbit satellites use, during their operation, high expansion-ratio nozzles of greater length than the inner volume of their carrier allows. Therefore, the engine overall length must be reduced during transport, and then extended for operation. Several types of nozzle extensions and nozzle extension means have been developed. For example, co-applicant, P. Jencek, has filed co-pending U.S. application Ser. No. 644,412, which discloses a telescoping, sleeve section around the fixed nozzle of the rocket engine. The sleeve is driven to form the extension. The extendible sleeve is advanced by inflating a pressure vessel which drives a support plate. The support plate supports radially-extending locking arms which engage the rear end of the nozzle extension. After the nozzle has been extended, a second pressure vessel and latching mechanism is utilized to jettison all nozzle-extending and deployment components out of the extended nozzles.
U.S. Pat. No. 4,125,224, issued to L. F. Carey, discloses a skirt-like nozzle extension. The device is adapted to be pleat-folded in a retracted position along a plurality of crease lines and subsequently unfolded to assume an unfolded frusto-conical shape. Carey discloses two methods for extending the nozzle. In a first method, when the rocket engine is fired, the initially developed gases impinge against the skirt and push it outwardly. However, with this method the skirt is likely to be damaged because it is caught in the flow of the exhaust and it is unlikely that the creases can be ironed out merely by the exhaust. In addition, the interference with the exhaust flow created by the skirt results in stability problems and lost performance. In a second method for extending the nozzle, actuators operable by a firing sequence control system extend the nozzle after ignition of the engine.